1. Field of the Invention
The invention relates to a device for detecting items having a transport device with two belt conveyors arranged one behind the other for transporting the items in a transport direction, wherein a slot is configured perpendicular to the transport direction between the belt conveyors, and having a scanning unit for contactless optical scanning through the slot of a contact surface of the items being transported.
2. Discussion
Such a device is known from DE 101 41 429 C1. The device is used, for example, in self-service cash register systems in shopping centers or similar and serves for the automated detection of items, in particular the detection of a marking identifying the items (barcode or similar) by means of an optical scanning unit. The optical scanning unit is arranged between two belt conveyors arranged one behind the other in a transport direction. The belt conveyors are positioned spaced apart from each other in such a way that a slot is formed between said belts extending perpendicular to the transport direction through which the scanning unit optically scans one contact surface of the items, on which the items are being transported, as they pass from the rear belt conveyor, as viewed in the transport direction, onto the front belt conveyor, as viewed in the transport direction. The remaining outer sides of the items are optically recorded, for example, by means of further scanning units so that the items can be identified safely and reliably, regardless of their orientation on the belt conveyors. The additional scanning units can be attached to an archway-shaped carrier arranged above the belt conveyors to form what is known as a tunnel scanner.
The scanning unit assigned to the slot is fixed in position to the belt conveyors, as are the additional scanning units, which can be provided as an option. The scanning unit typically contains a source for emitting optical radiation and a detector for receiving the radiation reflected from the items being transported on the belt conveyors. Usually the radiation involves wavelengths in the range of visible or UV light.
Although the device has basically proved itself, items can fall into the slot formed between the belt conveyors as they are being passed from the first belt conveyor to the second belt conveyor, with the result that the recording process has to be interrupted. In addition, in exceptional instances the items, or their packaging, can be damaged as said items are being passed from one belt conveyor to the next.